Swimming pools are enjoyed by many as a way of cooling off on hot summer days. The desired temperature of the swimming pool water for most comfortable enjoyment is in the range of about 70° F. to about 80° F. (approximately 21° C. to 27° C.). As such, controlling the water temperature to the comfort range is desirable. In cooler climates where the air temperature is typically lower, especially at night, heating the pool water with solar and other systems is well known. Such heating systems allow extended use of the swimming pool even when the temperature drops below 70° F. (21° C.).
In warmer climates, such as in the Southern United States, the ambient temperature can reach 100° F. (38° C.), or more, in the summer months. Swimming pool water in such conditions, particularly where there is no shade from the sun, can reach an uncomfortable 90° F. (32° C.), or higher, even with inground pools. Inground pools are commonly dug into the ground to depths of 8-10 feet or more to accommodate diving at the deeper portions of the pool. It is known that the temperature of the ground at a depth beginning at about five feet below ground level is substantially constant year-round, as recognized by many, including McClendon in U.S. Pat. No. 4,250,957, issued on Feb. 17, 1981. This constant temperature is in the range of approximately 55° F.-65° F. (approximately 13° C.-18° C.), depending upon the location, as noted by Azzam in U.S. Pat. No. 8,820,394, issued on Sep. 2, 2014.
While the bottom of inground pools at 8-10 feet is lower than the depth of about five feet at which the ground temperature is constant at around 55° F. (13° C.), the construction of the walls of the pool basin typically inhibits use of the lower ground temperature as a source of cooling for the swimming pool. Walls of inground pools are commonly constructed of concrete, such as Gunite material, or fiberglass, both of which are poor conductors of heat. Basin walls made of these materials thereby introduce a thermal barrier between the pool water and the ground which serves to insulate the pool water from the surrounding cool temperature of the ground. Further, manufactures often use an additional layer of insulation such as vinyl, either to the inner surface of the basin wall to keep heat in the pool water, or to the outside of the basin wall to keep the cold of the ground out. Sometimes, both inside and outside layers are used.
Certain efforts have been made to provide systems for cooling swimming pool water. One example is described by Argovitz in U.S. Pat. No. 7,624,589, issued on Dec. 1, 2009. The Argovitz apparatus comprises a cooler including a hollow tower that uses evaporative cooling principles to cool swimming pool water. Argovitz describes a number of other efforts that have been made to cool swimming pool water, which he indicates as being too costly or too complicated or cumbersome to install. Accordingly, there is interest in providing an improved system or apparatus that can effectively and inexpensively cool water in a swimming pool for the comfort of swimmers during hot weather conditions.